Rotation mechanism for rock drills



June 2l. 1927.

C. C. HANSEN ROTATION MECHANSM FOR` ROCK DRILLS Filed June 26, 1926 INVENTOR gzde.' 1 anden BY' Hfs' l Tommy Patented June 21, 1927.

uNiTED STATES PATENT OFFICE.

CHARLES C. HANSEN, 'or EASTON, PENNSYLVANIA, As'SI'GNoR "ro INGERSoLL-RAND COMPANY, oF JERSEY CITY, NEW JERSEY, A CORPORATION E NEW JERSEY.

ROTATION MECHANISM FOR ROCK DRILLS.

Application filed June 26, 1926. YSerial No. 118,737.

This invention relates to rock ydrills and more particularly to mechanism for rotating the drill steel.

The invention is of general application and possesses features of' special advantage when applied to pneumatically operated drills 'of the hammer type in which reciprocation of the hammer piston is adapted to cause rotation of the drill steel in one direct-ion of its travel.

One object of the invention is to rotate the drill steel effectively by means of a Spirally fluted rifle bar and to effectively hold the paivls in engagement with the ratchet of the rifle bar. Another object of the invention is to simplify the construction of the ratchet mechanism and to eliminate' breakable mechanical partsl in order to increase the durability of the` mechanism.

Other objects of the invention Will be in part obvious and in part pointed out hereinafter.

The invention will be more clearly understood by referencev to the drawing, vin which Figure l is a longitudinal Section through a hammer drill embodying the invention, and

Figure 2 is a cross Section through the ratchet mechanism of the rotating device.

Referring to the drawings, the invention is Shown as applied toa JI'orm of rock 'drill usually known as a drifter which is adapted to be mounted on suitable feeding mechanism (not shown) and is especially adapted for drillingholes lin a generally .horizontal direction. The drill comprises a reciprocating hammer piston A adapted to slide in a cylinder B. The type of ldrill here shown is of the so called valveless type in which the tail portion C of the piston A controls ports and passages for conducting motive Huid to either end of the cylinder B.

As is Well known in the art, the exhaust ot' spent motive iiuid is conducted to atmosphere through a pist-on controlled exhaust portI D situated substantially at the center of the path of the piston A Within the cylinder B. The tail portion C of the piston A is adapted to slide in a bore E of a ilanged bushing F suitably attached at the rear end of the cylinder B. A head block G is pro vided,- bein mounted on the rear end of the flanged bus ing F and having a suitable boss H a supply Veminerai:ien J tive Huid of any Suitable typey may be attached. y n

Y A passage K in the head block G connects the supply pipe J with a suitable throt-tle valve L in the flanged bushing F for controlling the flow of motive fluid to a pas- Sage O leading to ythe bore E. Motive fluid to the front end of the cylinder B is supplied through a port P, a paSSageQ and a front cylinder port R. For driving the `piston forward, motive fluid isvadmitted from the boreE to a passage S and a port T in the bore E controlled by the tail portion C of the piston A so that as the piston A1 moves back- Wardly or toward the head block G the port T is uncovered permitting motive fluid to flouv past the neck U ofthe piston A into the rear end of the cylinder. tool the rear face of the tail portion C is In this type of constantly exposed to live motive fluid preS- sure since the bore E is constantly in communication With the supply ofmotive fluid throughthe throttle valve L.

In drilling with this type of drill, it is desirable that the drill Steel be rotated in order not to jam in the hole being drilled.

VThis is accomplished by means of a rifle bar Y engaging a nut W fixed in the tail portion 'C of the. pistonA in a manner so that if the rifle bar be .held Stationary, vthe pistony A 'will rotate.` Preferably the rifle bar V is held against rotation on the up stroke of the piston A and permitted to rotate on the down vstroke consequently the piston A is caused to rotate on'its up stroke and vpermitted to move on its down stroke Se Without rotation.

i Rotation of the piston Ay is transmitted to a suitable drill steel. X by means of a 'chuck Y provided with a nut Z engaging a fluted nose of the piston A. The chuck Y being provided with a suitable bushing c of any desired form to engage the shank of the drill steel X. The cylinder B is also provided With a front cylinder Washer CZ adapted to prevent the escape of motive fluid from the cylinder into the interior of the chuck. As the flutes of the piston nose b are drawn back past the cylinder Washer cl, motive fluid under pressure may then escape into the interior of the chuck Y and thence throughthe usual bore (not shown) of the drill steel Kto blow the cuttings from the hele drilled.

The rifle bar V is provided with a head c having ratchet teeth f which are adapted to be en, ;a'ged by pawls (j to permit rotation of theI rifle bar V in only one direction. In this manner reciprocation of the hammer piston A causes rotation of the hammer piston in engagen'ient with the rifle bar V.

The rotation mechanism of which the rifle bar V forms a part includes a paWl ring L, shown more clearly in Figure 2, cut away as at j to admit the ratchet head e of the rifle bar and also to allow oscillation of the pawls .f/ which are mounted in cylindrical holes ,7c

in the pawl ring L. The pawls g have in most cases hitherto been pressed into engagement with the ratchet head c by means of spring pressed plungers mounted in a pawl ringsomewhat similar to the pawl ring it. @ne disadvantage of the former practice is that the springs wear and break very quickly.

By this invention the pawls are pressed into engagement with the ratchet head e by pressure of the motive fluid used for operating the piston A. To this end in this embodiinent of the invention, the pa'wl ring it is provided with a plurality of bores o and counterbores p coaxial or in alignment' with the boresfo. Plungers Q are provided to operate in the bores 0 and to press aga-inst the pawlsv g. Each plunger g is provided with a shank 7 fitting closely in the bore 0 and a head 8 fitting accurately in the counterbores kp. Motive fluid is supplied to the counterbores p from the passage O in the flanged bushing F to a relatively small pas sage t in the flanged bushing F and a communicating passage u in the paWl ring z, leading to an annular groove o in the periphery of the pawl ring. The annular groove -v leads to the counterbores 77. Y

As has been described above the bore E is constantly under pressure of live motive .fluid when the throttle valve L is open. Motive fluid will therefore leak along the rilie bar V into the chamber formed by the cut away portions j in the pawl ring and pressure Will therefore be exerted against the projecting ends of the Shanks 17 of the plungers (I. The heads a of the lilluigers q are however, of larger diameter than the shanks i" and the fluid pressure tending to press the pawls g into engagement with the ratchet head e will therefore be greater than the pressure against the Shanks i" tending to press the plungers out of engagee nient with the pawls g. Fluid under pressure is prevented from accumulating` at the bottom of the counterbores 79 under the heads s of the plungers q by providing atmospheric leak ports w leading through the head block G to atmosphere.

Preferably, the pawl ring 7L is clamped y tightly between the head block G and the flange of the bushing F to prevent ,rotation of the ring. A convenient construction for supporting the pawl ring 71, is shown in Figure l in which the head block G is counterbored at a" afnd the pawl ring L lits tight.A

ly within the counterbore.

The drill in this instance is provided with a water tube y passing longitudinally through the head block G, the rifle bar V and the piston A from a water connection a in the head block G into the bore (not shown) in the drill steel X.

Thus by the above construction are accomplished among others the objects hereinbefore referred to. y Y

I claim:

A rotation mechanism for percussive drills comprising a rifle bar having a ratchethead. a pawl ring surroundingsaid ratchet head, pawls to engage said ratchet head and sap` ported by said pawl ring, bores and counter'- bores concentric in said ring, differential piston plungers in said bores and counterbores to actuate said pawls, atmospheric leak ports at the bottom of said bores torelieve fluid pressure under the heads of saidvpiston plungers, and a circumferential groove in said paw] ring in connnunication with a source of constant pressure.

ln testimony whereof I have signed thisI specification.

n CHARLES C. lfIANSElfla 

